665642641181 has 8 divisors (see below), whose sum is σ = 760741660800. Its totient is φ = 570545425008.

The previous prime is 665642641121. The next prime is 665642641253. The reversal of 665642641181 is 181146246566.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665642641181 is a prime.

It is a super-2 number, since 2×665642641181² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665642641121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 463760 + ... + 1243526.

It is an arithmetic number, because the mean of its divisors is an integer number (95092707600).

Almost surely, 2^665642641181 is an apocalyptic number.

It is an amenable number.

665642641181 is a deficient number, since it is larger than the sum of its proper divisors (95099019619).

665642641181 is a wasteful number, since it uses less digits than its factorization.

665642641181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 901723.

The product of its digits is 1658880, while the sum is 50.

The spelling of 665642641181 in words is "six hundred sixty-five billion, six hundred forty-two million, six hundred forty-one thousand, one hundred eighty-one".